Lifting-jack.



E. R. PENROSE.

LIFTING JACK. APPLICATION FILED MAR.17, 1913.

1,078,374. Patented Nov. 11, 1913.

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EDWARD'R. rnlvnosn, or toennsronr, INDIANA, nssre'ivon ro none compan or oHIcAeo, ILLINOIS, a oo aronerxon or ILLINOIS.

Specification of Letters Patent.

Patented Nov; 1 1, 1913.

Application filed March 17, 1913. Serial No. 754,774.

To all whom it may concern:

Be it known that I, EDWVAHD It. Panacea, a citizen of the United States, and residing at Logansport, in the county of Cass and State of Indiana, have invented certain new and useful improvements in Lifting-Jacks, of which the following is a specification, refercnce being had to the accompanying drawmgs.

lrl v invention relates generally to the class of lifting ache, and more particularly to the application of an improved thrust and frie tion mechanism in a jack casing, wherein the degree of frictional resistance is proportional to load pressure.

This invention has for its principal object the prmision, of certain means more specifically set forth hereinafter, whereby the jack screw is positively prevented from acciden- E f pawls mounted in suitable recesses in the innor wallsof the depending flange id for e11 tally running down in the eel: under a load.

This, together with such other objects may hereinafter appear, or are incident to my invention, I attain by means of a construction illustrated in preferred form in the accompanying drawings, wherein Figure 1 is a vertical section of a lifting jack embodying my invention.

I i'gure 2 is a sectional view on the line II II of Figure 1 and 4 Figure 3 is a partial view in perspective showingthe engagement of a pawl with the gear teeth.

In practice it frequently happens that a jack of this character while sustaining a heavy load will run down bringing the load 1 that when the bevelgear 10 is rotated to rise in the jack by means of the pinion 11 and operating mechanism 13 the pawls 17 ride .easi-ly over the teeth of the gear so that it with it, and it is obvious that such accidental lowering is an objectionable feature. It is my object to overcome this by providing an independent annular member removed from the upper face of the gear by a plurality of anti-friction members said member being provided with a depending annular flange or lug carrying a pawl which rides over the gear teeth so that the gear freely rotates in one direction, while on rotation in the opposite direction the annular member has synchronous movement with the gear through the engagement of the pawl with the gear teeth, whereby accidental lowering of the screw and shell is effectually and positively prevented.

In describing my invention the numeral 4 indicates a stationary standard with its sup-- porting base 5, and having a close fit about the standard for relative movement t re with is a shell 6,-its upper end being inc-loscd to form a cap 7. l vithm the upper end of the standard is mounted the usual operating out '8 carrying the screw 9. The latter has keyed to its upper reduced end a bevel gear 10 which meshes with a bevel pinion 11 formed upon the stub shaft 12, the shaft being journaled in the shell and adapted to receive rotation from any suitable operating mechanism 13 to raise and lower the ack, as will be understood.

interposed between the upper face of the gear and the cap 7 of the shell is an annular bearing plate 1% having an annular depending flange 1.4:, and between these two mem- 3 hers are interposed plurality of anti-frictlon members 15.

plate l t and the shell cap is a frlction dish 16.

Positioned between the The numeral 17 rcyn'escnts a plurality of ga gcment with the gear 10, each pawl havmg movement on its pivot pin 18 and yield ingly held against the gear teeth by a spring quently occupy withrespect to the periphery gof the gear they may all have positive engagement with the teeth.

From the foregoing it will be apparent freely rotates to lift the shell relative to the standard to raise a load.

The jack may safely be an at an time when the load has been raised to its prede termincd position, as any reverse rotary movement of the gear due to load pressure and leading to the accidental running down of the screw and shell, is effectually prevented by the annular member 14; through its pawls 17 which have positive engagement with the gear teeth. Under these circum stances the member 14 is stationuary as the frictional resistance due in part to theinterposition of the friction disk, overcomes any tendency to reverse rotary motion of I during the operation of lifting the load, or i the gear. his is particularly advantageous in high-speed jacks where a coarse threaded screw is employed for quick running up of the load.

In lowering the load the mechanism 13 is operated to overcome the frictional resis ance above referred to, the gear 10 and an nular member 14L having synchronous rotative movement during this operation, which insures a degree of safety not otherwise obtained. T 1e direct engagement between the bearing plate pawls and the teeth of the gear is an advantageous feature, and is further nromotive of an economical and simple arrangement of a few parts leading to a maximum degree of efficiency.

From the foregoing, the essential features, elements and the operation of the device, together with its simplicity and other advantages thereof, will be clearly apparent.

Having thus described my invention and illustrated its use what I claim as new and desire to secure by Letters Patent is the following:

1. In a lifting min the combination of a standard and a member movable thereon, a screw for said movable member provided with a gear, an annular member interposed between said gear and said movable memher, and means carried by said annular member adapted to engage with the teeth of the gear for synchronal movement of the said member and gear in the one direction, the said means permitting the gear to have free and independent movement in the other direction.

2-. In a lifting jack, the combination of a standard and a movable member thereon, a screw for said movable member and provided with an actuating gear, an annular member between said gear and said movable iember in frictional contact with the latter, and a pawl carried by the said annular member adapted to engage with the teeth of the gear whereby the said gear and annular member have similar movement in one direction, but permitting independent movement of the gear in the other direction.

3. In a lifting jack, the combination of a between the movable member and gear pro vided with a depending portion terminating below the upper face of the gear, and means interposed between said depending portion and gear adapted to engage the teeth of the latter for synchronous movement in one direction, but permitting the gear to have independent movement in another direction, substantially as described.

4. In a lifting j ack, a standard and a movable member thereon, a screw and nut for raising and lowering the movable member, means for rotating said screw comprising a pair of gears having relatively different sized teeth widths, an annular plate interposed between the screw and the movable member, and a pawl carried by the annular member and adapted to connect it with the gear having the greater width of teeth for similar rotation of these members when lowering the jack, the excess in teeth width of the last mentioned gear permit-ting a continuous connection between the gear teeth and the annular plate irrespective of any position taken up by the pawl.

5. A lifting jack comprising in combination a standard, a shell movably mounted on the standard, a screw threaded into the standard for lowering and raising the shell, a bevel gear on the screw having teeth extending from face to face of the gear, an annular plate interposed between the gear and the shell, a pawl carried by the plate having a ratchet engagement with the teeth adjacent the largest diametered face of the gear, and a second bevel gear for turning the first gear engaging the teeth of the first gear adjacent the smaller diametered face thereof.

In testimony whereof I have hereunto signed my name in the presence of the two subscribed witnesses.

EDVARD R. PENROSE.

Witnesses:

XV. HERBERT FowKEs, M. M. MOORE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

